Reducing Branch Misprediction Penalty via Selective Branch Recovery

Branch misprediction penalty consists of two components: the time wasted on mis-speculative execution until the mispredicted branch is resolved and the time to restart the pipeline with useful instructions once the branch is resolved. Current processor trends, large instruction windows and deep pipelines, amplify both components of the branch misprediction penalty. In this paper, we propose a novel method, called Selective Branch Recovery (SBR), to reduce both components of branch misprediction penalty. SBR exploits a frequently occurring type of control independence ? exact convergence ? where the mispredicted path converges exactly at the beginning of the correct path. In such cases, SBR selectively reuses the results computed during mis-speculative execution and obviates the need to fetch or rename convergent instructions again. Thus, SBR addresses both components of branch misprediction penalty. To increase the likelihood of branch mispredictions that can be handled with SBR, we a...

• Type: Conference
• Year: 2004
• Where: HPCA
• Authors: Amit Gandhi, Haitham Akkary, Srikanth T. Srinivasan
• Keywords: Branch Misprediction Penalty, Branch Mispredictions, Computer Architecture, HPCA 2004, Selective Branch Recovery